Hi Venkat
Experience is not a check list but a continual learning process. Just because you have done something once is not enough. Less than 5 years experience is an indication of a junior/fresher level. With 3 years experience is does seem like you have done a lot of small or short projects - this is not a bad thing at all.
The other indicator of experience is the number and types of implementations you have done. End to End Implementation does count quite a bit to show that you are going through all of the project phases and starting in the Development system through to Production. Other types of projects are the green fields (build production from scratch) vs the technical upgrades vs increase scope of functionality. All of them have different challenges and experience to obtain.
There is always something to learn and when you go to a new project it can include new way of work, different system, changes to business process. It is also a way to network and meet new colleagues who one day may ask for you to join their projects, etc.
I think you should weigh up your options on a career (not carrier) change based on what are you currently doing now and compare to the new opportunity: what will you gain versus what will you lose.
I hope this clarifies your concern as I am still unsure what your concern is? End of the day there is always something new to learn (and sometimes projects can teach you the valuable lesson of what not to do) but it will not be handed to you on a silver platter or spoon fed. You have to look at each job and find the opportunity yourself for a successful career.
Regards
Colleen.